Manufacture of metallic alloys and articles made therefrom



Patented Aug. 27, 1935 MANUFACTURE OF METALLIC ALLOYS AND ARTICLES MADE THEREFROM Charles Philip Miller, Romlley, England, assignor to Carboloy Company Inc., a corporation of New York No Drawing. Application December 5, 1931, Serial No. 579,348. In Great Britain April 21,

13 Claims. (01. 148-215) ,This invention has reference to metallic alloys and to articles made therefrom and has for its object to provide an alloy which is particularly suited for cutting tools and which is capable of being easily worked so as to manufacture it into articles required, the articles so produced being degree of hardness without scaling or distorting 5 capable of receiving a high degree of local hardby heating the forged or machined article to a ness without detracting from the general toughtemperature varying from 250 C. to 650 C. ness of the article as a whole. According to one embodiment of the invention In the manufacture of hard metallic steel alas applied by way of example to the manufacture loys as at present used e. g, for cutting tools it of an alloy and to a cutting tool for a lathe made is known to use high percentages of metals such therefrom, the alloy is prepared by melting in a as tungsten, molybdenum, chromium and cobalt; suitable furnace which should be as free as posthese alloys have however as a general rule been sible from any trace of carbon. The greater part hard and brittle, and consequently have been of the alloy is made up of iron, with cobalt incapable of being forged or machined; as they from 20% to 35%, tungsten or molybdenum todo not respond to heat treatment and can only gether or separately totaling from to 30%, be cast and afterwards ground to the desired vanadium up to 3% and manganese up to .8%. shape. If such alloys have not these hard and An alloy so made is cast into moulds and the inbrittle characteristics they are similar to high gots from the moulds are reheated, being kept speed steel and contain substantial proportions as far as possible free from contact with carbon of carbon and chromium as essential constituand forged, rolled, pressed or otherwise treated ents, they can be forged and machined, but in as required in a manner similar to the treatment common with high speed steels which are hardof high speed steels. ened from yellow to a white heat, owing to (115- After this treatment the alloy is annealed and tortion and scaling during this process it is necafter annealing is found to be easily machineable. essary for articles made from them, to be ground A further heat treatment is now given to the or stoned in order to make them accurate, as alloy. In this heat treatment the temperature when used as tools and for which efilcient cutis raised to from 1,000 to 1,400 C. the actual ting edges are required. temperature used being determined by the ulti- It is also known that these alloys can be immate hardness required and also by the compoproved in cutting emciency by reheating articles sition of the alloy. After this heating the alloy such as tools made from them to temperatures is cooled quickly and as a result of the treatup to about 650 0., though very little extra hardment it assumes a tough state or condition and ness is obtained by this treatment, and if the unlike high speed steel after a similar. treattreatment be carried too far the result may cause ment it can be filed and machined, the metal proa softening and deficiency in the cutting powers duced is' thus quite unlike high p d t of the tool. Thus this secondary treatment is of After this treatment the toughened metal can 1J8 very little use for regulating the hardness of the filed and machined into the desired shape. Such as material, as once the alloy is made softer by into a. lathe cutting tool and the made tool is this reheating process any further heat, a for next hardened in order to give it its cutting efliinstance heat generated during use, will in gen-- ciency. Th s hardening Consists in r h atin eral make the alloy still softer and more pr ne part or the whole of the tool or article to 250 C. to wear. to 650 C. depending on requirement, and after By means of the present invention, alloys are the heating the cooling is effected as is convenprovided which have a high degree of hardness ient n required, for instance a quick oli g especially at high temperatures and very desirwill be necessary to prevent the heat travelling to able cutting properties when employed as metal other parts of the articles when local heating is cutting tools. employed to get local hardening and thus the According to this invention metallic alloys and tip 01 Cut d of a @001 can be given a fl- 50 articles made therefrom are as far as possible cient cutting edge without embrittling the tool. free from carbon, and contain-cobalt (from In general the hardening increases with the 20% to tungsten or molybdenum either temperature, and the hardness can be regulatedtogether or separately from 15% to 30% the balfrom the toughened machineable state to the ance being iron, vanadium up to 3% and mangamaximum hardness attainable by the alloy, and p nese up to .6% may be added to facilitate forg- I quired form and can be hardened to any required this hardness may bejincre'ased to a point which would be too brittle, for certain purposes, it is consequently a matter in which experience must be used to decide the required temperature for tools. or articles made for certain specified purposes.

when a toolot this alloy is heated to a temperature below that which gives it its maximum hardness in order to obtain a less brittle tool, then any heat generated in use will, ii of the necessary intensity, have the eflect of hardening the part effected still further, thus helping to resist wear. The heat generated by use will have the reverse eiIect to that obtained when high speed steel is used and where hardness has been sacrificed to toughness.

A suitable alloy for tools has been made comprising-cobalt 30%, tungsten 23%, vanadium 1.5%, manganese .2%, carbon, silicon and other impurities not exceeding .3% together, the balance being made up 01' iron. With an alloy of this composition the first heat treatment after annealing and rough machining consisted in raising the temperature to 1,280 C. and after raising to this temperature and cooling quickly the tools could be filed to shape comparatively easily. After filing to shape the tools were heated to 500 C. for tools to be used on steel for heavy work and up to 630 C. for finishing tools for cast iron and brass.

What I claim as my invention and desire to secure by Letters Patent is:-

1. A substantially carbon free metal cuttin tool, said tool being age hardened and consisting of about 20% to about cobalt, about 15% to about 30% metalifrom a group consisting of tungsten and molybdenum, an appreciable. quantity up to about 3% vanadium, an appreciable quantity up to about .8% manganese, the remainder of said alloy, except for minor impurities, being iron.

2. An alloy metal cuttingtool containing about 20 to 35% cob it, about 15 to 30% of metal from 1 a group consis ing of tungsten and molybdenum, from a fractional quantity up to about 3% vanadium, an appreciable quantity up to about .6% manganese, the remainder of said alloy, except for minor impurities, being iron.

3. A substantially carbon-free alloy comprising about 30% cobalt, about 23% metal from a group consisting of tungsten and molybdenum, about 1.5% vanadium, about .2% manganese, the remainder 01' said alloy being iron.

4. An age hardened, hard. tough alloy containing about 20 to 35% cobalt, about 15 to 30% of metal from a group consisting of tungsten and molybdenum, an appreciable quantity and up to about 3% vanadium, an appreciable quantity and up to about .6 manganese, the remainder erf said alloy, except for minor impurities, being 5. An alloy heat treated at 1000 c. to 1400 C., quickly cooled and hardened by reheating at 250 C. to about 650 C., said alloy containing about 20 to 35% cobalt, about 15 to 30% of metal from a group consisting oi tungsten and mo1ybdenum, an appreciable quantity and up to about 3% vanadium, an appreciable quantity and up to 7 about .6% manganese, the remainder of said alv loy, except for minor impurities, being iron.

6. The process of producing a substantially carbon free alloy consisting of. about 20% to about 35% cobalt, about, 15% to about 30% of metal from a group-ponsisting'or tungsten and molybdenum, an a ppreciableguantity up to 3%- vanadium, a i. apnrejciableji up to .8%

. aomisso manganese, the remainder of the alloy being iron which comprises heating the alloy at a temperature not appreciably lower than 1000 C. and

below the melting point of the alloy and quenching the alloy to thereby toughen it and permit machining, reheating only a portion of the alloy to a temperature of about 250 C. to 650 C. and

cooling the alloy to thereby produce local hardening of the alloy.

'l. The process of producing a substantially 10 carbon free alloy cutting tool consisting of about 20% to about 35% cobalt, about 15% to about 30%oi metal from a group'consisting of tungsten and molybdenum, an appreciablequantity up to 3% vanadium, an appreciable quantity up to .8% manganese and the. balance iron, which comprises heating the alloy at a temperature not appreciably lower than 1000 C. and below the melting point or the alloy, quickly cooling the alloy, machining the alloy into a desired shaped toolprovided with a cutting edge portion, re-- heating only said cutting edge portion to a temperature below 1000 C. but not lower than 250 C. and cooling the tool to thereby produce local hardening.

8. The process of producing a hard, tough, substantially carbon-free alloy consisting of about 20 to 35% cobalt, about 15 to 30% of metal from a group consisting of tungsten and molybdenum, an appreciable quantity up to about 3% vanadium, an appreciable quantity up to about .6% manganese, the remainder of said alloy being iron, which comprises heating said alloy to an elevated temperature not appreciably lower than 1000 C. but below the melting point of said alloy to a temperature of 1000 C. to 1400 C.

but below the melting point of said alloy, quenching said alloy and reheating it to a temperature of 250 C..to 650 C. p

10. The process of .producing a hard, tough, substantially carbon-free alloy consisting of about 20 to 35% cobalt, 15 to 30% 01' metal irom a group consisting of tungsten and molybdenum, an appreciable quantity and up to about 3% vanadium, an appreciable quantity and up to about .6% manganese, the remainder of said alloy being iron, which comprises casting said alloy'into ingots, reheating said ingots out of contact with carbon, mechanically working said, ingots, an-

- nealing said mechanically worked alloy, heating the alloy to 1000 C. to -1400 C., cooling it and reheating it to 250 C. to 650 C. v a

11. An alloy containing about 30% about 19% tungsten, about 3% molybdenum,

about 2% vanadium, about 0.5% manganese, the

remainder of the alloy, except for minor impurities, consisting of iron.

12. A substantially carbon free alloy containing about 20% to-about 35% cobalt, about 15% to about 30% of metal from a group consisting of tungsten and molybdenum, an-appreciable quantity up to about 3% vanadium, an appreciable quantity up to about 0.8% manganese, the recobalt,

mainder or said alloy, except for, minor impurium, an appreciable quantity u to about 0.8% tles,'conslsting of iron. manganese, the reminder of said alloy, except 13. The process of producing a substantially for minor impurities, consisting of iron, which. carbon free alloy containing about 20% to about comprises heating said alloy at a. temperature 5 35% cobalt, about 15% to 30% of metal from a above 1000 0., quickly cooling the alloy,'and 5 group consisting of tungsten and molybdenum, thereafter aging the alloy.

CHARLES an appreciable quantity up to about 3% vanadi- PHILIP MILLER.

CERTIFICATE OF CORRECTION.

Patent No. 2,012,890. August 27, 1935.

' CHARLES PHILIP MILLER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, second column, after line 51, insert the following paragraph:

In quickly cooling the alloy from a temperature of 1000C. to 1400C.. the quenching action need not be as drastic as with ordinary steel. For example, it is sufficient to cool small nieces of the alloy in the open air and larger pieces may be quenched satisfactorily by using an air blast. Oil quenching may be employed when convenient but in general it is not as satisfactory as air quenching.

And that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 8th day of October, A. D. 1935.

' Leslie Frazer (Seal) Y Acting Commissioner of Patents. 

